Cooling air cooler for a gas turbine engine

Abstract

A gas turbine engine having a compressor and an air-cooled turbine is provided with a cooling system for decreasing the temperature of the turbine cooling air. A compact heat exchanger, rotatable with the compressor, receives a portion of the pressurized air which is bled from the compressor. Relatively cool engine lubrication oil is pumped through the heat exchanger into heat exchange relationship with the pressurized air, thereby cooling the air and heating the lubrication oil. The cooled air is then routed to and circulated through the turbine blades to provide improved internal cooling thereof. The heated lubrication oil is collected from the heat exchanger and routed to a second heat exchanger wherein it is placed in heat exchange relationship with engine fuel to recover the heat extracted from the compressor bleed air and to return the heat to the engine operating cycle. The cooling system is designed to contain the lubricant in the unlikely event of a leak developing in the heat exchanger. Incorporation of the heat exchanger of the present invention into a gas turbine engine permits a reduction in the quantity of compressor air required for turbine rotor blade cooling and, thus, provides an improvement in engine performance.

Having thus described the invention, what is claimed as novel and desired to be secured by Letters Patent of the United States is: 
     
       1. A gas turbine engine comprising a compressor for pressurizing air, a turbine having blades of the air-cooled variety, an engine lubrication system, and a heat exchanger rotatable with said compressor and having a first inlet in fluid communication with said compressor for receiving pressurized air therefrom, a second inlet in fluid communication with said lubrication system for receiving lubricant therefrom and an outlet for said pressurized air in fluid communication with said turbine blades. 
     
     
       2. A system for cooling a turbine of a gas turbine engine having a compressor for pressurizing air and a lubrication system comprising: means for extracting a portion of the compressed air from the compressor;   a heat exchanger connected to and rotatable with said compressor and turbine;   means for routing the extracted portion of air into said heat exchanger;   means for routing lubricant from said lubrication system into said heat exchanger wherein it is placed in heat exchange relationship with said extracted portion of air; and   means for routing said extracted portion of air from said heat exchanger and into said turbine.   
     
     
       3. A gas turbine engine comprising a compressor for pressurizing air; a turbine; a shaft drivingly connecting said compressor and turbine; a lubrication system; an internal cavity defined in part by said compressor, said shaft and said turbine; and a first heat exchanger rotatable with said compressor and turbine disposed within said cavity, said first heat exchanger being in fluid communication with said compressor for receiving a portion of heated compressed air therefrom and with said lubrication system for receiving a relatively cool lubricant therefrom, said air and said lubricant being placed in heat exchange relationship within said first heat exchanger, thereby heating said lubricant and cooling said air. 
     
     
       4. The gas turbine engine as recited in claim 3 wherein said first heat exchanger comprises a pair of generally concentric inner and outer shells defining an annulus therebetween; and a plurality of hollow finned tubes spaced circumferentially about said annulus and wherein the extracted portion of air is routed through said annulus between said tubes and the lubricant is routed through the hollow interior of said tubes. 
     
     
       5. The gas turbine engine as recited in claim 3 further comprising a combustor wherein pressurized air from said compressor is mixed with a fuel and combusted, a second heat exchanger, means for directing the heated lubricant from said first heat exchanger and through said second heat exchanger; means for serially routing fuel through said second heat exchanger and into said combustor, thereby heating said fuel prior to combustion. 
     
     
       6. A system for cooling a turbine of a gas turbine engine having a compressor for pressurizing air and a lubrication system, comprising: a radial inflow impeller rotatable with the compressor for extracting a portion of the compressed air therefrom;   a heat exchanger having generally concentric inner and outer shells defining an annulus therebetween, a plurality of hollow finned tubes spaced circumferentially about the annulus, a pair of bulkheads extending between the inner and outer shells to support the tubes, and a generally annular duct surrounding the outer shells;   means for routing the extracted portion of air through said generally annular duct and into the annular space between said tubes;   means for routing lubricant from said lubrication system into said heat exchanger and through the hollow interior of said tubes; and   means for routing said extracted portion of air from said heat exchanger and into said turbine.   
     
     
       7. The cooling system as recited in claim 6 wherein said annular duct is in fluid communication with the annulus between said inner and outer shells. 
     
     
       8. The cooling system as recited in claim 7 wherein each of said tubes includes a plurality of laterally projecting and longitudinally extending fins, one end of said fins being contoured to guide the flow of extracted air from said annular duct and through said outer shell into said heat exchanger. 
     
     
       9. A system for cooling a turbine of a gas turbine engine having a compressor for pressurizing air and a lubrication system, comprising: means for extracting a portion of the compressed air from the compressor;   a heat exchanger having generally concentric inner and outer shells defining an annulus therebetween, a plurality of hollow finned tubes spaced circumferentially about the annulus, and a pair of bulkheads extending between the inner and outer shells to support the tubes;   means for routing the extracted portion of air into said heat exchanger; and   a collector having a generally corrugated wall defining a plurality of chutes, alternating chutes being in fluid communication with said lubrication system and the hollow interior of said tubes wherein the lubricant is placed in heat exchange relationship with the extracted portion of air, and the remaining chutes being in fluid communication with the annular space between tubes and said turbine to be cooled.